Apple isn’t rolling up to the Wells Fargo and accepting a 5% spread. If you personally want to exchange a ton of money open an interactive brokers account and you’ll pay 0.08 basis points (0.0008%) minimum $1. If you don’t want to trade that much, check out compareremit.com and see what people are paying retail, it’s actually very competitive. In the popular USD-INR corridor you could pay close to mid market rates plus zero commission. This is a solved problem.